What is Normal Warming for the New iPad?

I am on my second new IPad since the release. I still experience some warming on the lower left side of the iPad. I'm a pretty gentle user- Internet, reading, movies, etc...What is "normal", since some posting in this forum are reporting no warming issues at all. Does this mean your device remains cool through all levels of use? I am trying to figur out if I still have a defective product & need to swap again. I have never experienced warming in any hand-held Apple device I have owned, until this one.

Thanks!